Self-locking tool shank



Patented Mar. 16, 1943 UNITED STATES PAT EN T O ve",`313,8'5t

SELF-toenam Toi.

Edward i. Armstrong, Columbaohio, aS- n'or vt9 The Union Foi-katia Hoe Company, Columbus, Ohio, a corporation of Ohio Appnat'ion February 1s, 1941, serial Nt; 318,779

1 claim. (c1. ede-'41) This invention relates to hand-wielded tools or implements, particularly those having separate handle and body members, such as in farm and garden tools, wherein the body or blade member of such a tool is formed with a shank adapted to be received within a close-iitting socket formed in the contiguous end of a handle.

Considerable difliculty is encountered in tools of this description in the matter of securely and permanently uniting such tool parts so that underv conditions of use or severe service, the same will not separate or come apart. In many tools of the type specified, a tapering metallic tool shank, usually polygonal in cross section is, at the time of manufacture of the tool, forcibly driven into a longitudinally and axially disposed socket formed inV one end of a wooden handle. While this arrangement is simple and economical (factors which industry requires), it is open to the objection that the shank readily becomes loosened in the socket, as the result of wood; shrinkage or the movement or working of the shank in the socket when the tool is in use, causing the tool body or blade to separate from the handle.

Accordingly, it is'aprimary object of the present invention to provide improved means, in association with the shank of such a tool, by which, when the shank is inserted in the handle socket, relative separating movement between the handle and the shank in a longitudinal direction is preeluded.

Another object resides in providing the tool shank with a tang or prong member, the latter being so disposed that when the shank is driven into the handle socket, the said member will not interfere with the inserting operation but, further, is so formed that following such an insertion, any force tending to withdraw the shank will result in causing the prong or prongs of said member to bite or be forced into the wooden body of the handle, thereby establishing such high forces of resistance as to render it virtually impossible for the shank and handle to separate under ordinary anticipated conditions of tool service.

Still a further object of the invention resides in the provision of an improved self locking tool shank which is simple in construction, convenient to apply and economical in design.

For a further understanding of the invention, reference is to be had to the following description and the accompanying drawing, wherein:

Fig. 1 is a View partly in horizontal section and in plan, disclosing the improved shank fastening means comprising the present invention;

,frig.A 2 isa transversesectional view taken on theplane, indicated bythe line Ivi-11 of Fig. V,1; Fig. 3 isa detail perspective `View of the tool Shank; M l. .i

Fig. 4 is a similar view of the pronged fastening member for theshank; Y. M s Y.

1 Fig. 5 is a detail plan view illustrating ed form of the invention.

Fig. 6l is a fragmentary 1ongitudina1setioai View tei-ken through a tool shank and -h'an'x'ilv of a further modified forni. A y

Referring more particularly to the drawing, thenumeral l, designates the body or blade of a handled tool such, for lexample;` as a pitch fork, hashovel, or other hand-welded tool, and the numeral 2 designates a' wooden handle 'of .any suitable length, depending upon the uses to which the tool is placed, Preferably, the handle 2 i'sof wood, although other suitable materials may be used. l To'unite thebody or blade tvv-ith thehandlel, the latter is provided at one end with an axially disposed, longitudinally' extending socket v3, one end of the socket being closed and the other, aft the end-of thehandle, being yopen. This socket is adapted to receive the shank 4 of the body or blade l of the tool. Preferably, the shank 4 is integrally formed with the body or blade I and tapers toward its outer end, being polygonal in transverse cross section. As usual, the shank is somewhat greater in cross sectional dimensions than the original corresponding dimensions of the socket 3, so that when the shank is driven into the socket, the walls of the latter will exert a compressive action on the surfaces of the shank to hold the latter frictionally in connection with the handle. Also, the outer portions of the handle 2, around the socket 3, are reenforced by a metallic sleeve or ferrule 5 to prevent the handle from splitting when the shank is driven into the socket or when the tool is subjected to thepractical uses for which it is adapted.

In a preferred form of the present invention, as shown in Fig. 1, the outer end of the shank 4 is provided with a head 6 which terminates in lateral shoulders 1. Applied to the outer end of the shank is a metallic fastening clip 8, the me-v dial portion of which is shaped to conform to the configuration of the head 6, the clip being further formed to include inwardly and laterally directed lips 9 which engage with the shoulders 1 and retain the clip on the outer end of the shank, the lips 9 terminating in oppositely disposed resilient arms l0, the free ends of which tend to spread apart and constituting retaining prongs or tangs.

a modi;

ends of the arms l to bite or be forced into the Wooden body of the handle adjacent the socket,

as indicated in Fig. l, thereby establishing such high forces of resistance as to render it virtuallyY impossible for the shank and handle to separate under all ordinary conditions of tool usage. desired, and to accentuate this feature, the socket 3 may be provided With shoulders H with whichV the free ends of the resilient arms I0 may engage. It will be understood, however, that the shoulders IlY may or may. not be employed. The construction here disclosed provides simple and effective means for permanently connecting a tool blade or body with an associated handle.

The invention is, of course, subject to certain modications Without departing from its essential features of construction. As illustrated in Fig. 5, the resilient arms Illa may be secured to the opposite sides of a shank 4a by means of welding or riveting, the arms lila, in this instance, being formed from separate pieces, rather than the integral one-piece construction disclosed in Fig. 1.

In both forms of the invention above described, the retaining prongs or tangs have been carried on the outer sides of a tool shank formed for insertion in a socketed handle. The reversal of this structure will Work equally well as illustrated in Fig. 6, wherein the tool head extension 1lb has a longitudinally extending socket I2 with converging side Walls for the reception of the tapered end I3 of a handle It. Anv annular shoulder l5 may be provided, ii desired,v adjacent to the end of the handle for engagement by retaining tangs .I6 which are formed With the socket Walls. The

free ends of the tangs I6 are directed toward the inner end of the socket and may be sharpened or not as desired. Due to the resiliency of the material from which the tool head is constructed and the construction of the tangs I6, the latter will snap behind the shoulder l5 When the handle is fully inserted and serve to positively retain the handle and head in assembled relationship. If a pulling force is appliedlto the handle in an attempt to effect the Withdrawal from the socket,

y the sharpened ends of the tangs Will dig into the handle and resist movement thereof relative to -the tool head.

Other modifications may be resorted to without departing from the scope of the invention as the latter has been'set'forth in the following claim.

What is claimed is:

In a tool of the type having a wooden handle member and a separate metallic -body member, the handle member being provided with a longitudinally extending axially disposed Vsocket in one end thereof, a shank projecting from said mem-` ber for reception within said socket, a tapering shank projecting from said body member, a head on the outer end of said shank, said head providing perpendicularly disposed shoulders facing toward said body member, a handle-securing metallic clip positioned on the outer end of said shank, said clip having an intermediate portion shaped to receive the head on the shank, said intermediate portion terminating in a pair of spaced resilient arms arranged on the opposite sides of said shank, the combined thickness of said head and clip conforming substantially to the Width of the handle socket, shoulder means formed on said clip at the junctures of the arms thereof with said intermediate portion and adapted for engagement with the shoulders on said shank, the outer ends of said arms being sharpened and adapted to project angularly away from said shank in order to be embedded inv and partially penetrate the wooden body of said handle member upon initial Withdrawal move-` ment of said shank from said socket.

EDWARD J. ARMSTRONG. 

